Interference Filter for Sub-Micron Particle Imaging
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Solution Overview
Problem
Digital holography imaging systems face challenges in imaging small particles or structures less than 1 μm due to a large background signal from non-scattered light, which reduces imaging quality and requires invasive methods for smaller samples.
Innovation Solution
An imaging system with an interference filter that selectively reduces transmittance of non-scattered light based on incident angle, enhancing the relative intensity of elastically scattered light, allowing for improved signal-to-noise ratio and accurate detection of scattered light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If digital holography imaging is used to image small particles or structures less than 1 μm, then non-invasive imaging is achieved, but imaging quality deteriorates due to large background signal from non-scattered light
Solution Approach 1:
The patent extracts and removes the harmful background signal (non-scattered light) from the detection path using an interference filter. The filter selectively blocks light traveling in the forward direction (non-scattered light) while allowing scattered light from small particles to pass through, thereby eliminating the dominant background noise that prevents imaging of sub-micron particles without sample damage
Solution Approach 2:
The patent changes the detection parameter from intensity-based detection to angle-based filtering. By introducing an interference filter that discriminates based on light propagation angle, the system can distinguish between non-scattered light (0° angle) and scattered light (non-zero angles), enabling detection of weak scattered signals from small particles that would otherwise be masked by the intense forward-propagating light
2Measurement precision
If standard imaging methods are used to improve imaging quality of small samples, then invasive methods are required, but sample integrity deteriorates due to sample damage
Solution Approach 1:
The patent introduces an interference filter as an intermediary component between the sample and detector. This filter acts as a mediator that selectively transmits scattered light while blocking non-scattered light, enabling high-quality imaging of small particles without requiring invasive staining or labeling methods that would damage the sample
3Illumination intensity
If non-scattered light is included in detection, then signal intensity is maintained, but signal-to-noise ratio deteriorates due to dominant background signal
Solution Approach 1:
The patent segments the light signal into two distinct components based on propagation angle: non-scattered light (forward-propagating, 0° angle) and scattered light (diffuse, non-zero angles). The interference filter applies different transmission characteristics to each segment, completely blocking the non-scattered component while transmitting the scattered component, thereby isolating the weak signal of interest from the dominant background
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enables high-quality imaging of small particles or structures by increasing the proportion of scattered light detected, reducing background noise, and allowing for non-invasive imaging without damaging the sample, enabling multiple analyses and long-time imaging.
Implementation Method 1
the light source is configured to generate illumination light of a single wavelength for illuminating the sample to induce elastic scattering of the light of the single wavelength by the sample
Implementation Method 2
the interference filter is configured to provide transmittance of the single wavelength in dependence of an angle of incident light, wherein the interference filter is configured to selectively reduce transmittance of light having an incident angle on the interference filter corresponding to non-scattered light
Data Source
AI summary
According to an aspect of the present inventive concept there is provided an imaging system for imaging of a sample, comprising a light source, an interference filter and a detector, the light source generates illumination light of a single wavelength to induce elastic scattering of the light by the sample, the interference filter selectively reduces transmittance of light having an incident angle on the interference filter corresponding to non-scattered light, the detector is configured to detect a two-dimensional representation of the elastically scattered light transmitted by the interference filter.